CR-39 Plano Demo Lenses Clear Lens Blanks 25 Pairs (Box of 50) 71 x 1.8 x 6 Base

Description

CR-39 Plano Demo Lenses Clear Lens Blanks 25 Pairs (Box of 50) 71 x 1.8 x 6 Base
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Price Shown Is For 25 Pairs (Box of 50 CR-39 Plano Demo Lenses)
71mm x 1.8mm x 6 Base
Tintable
Slight Imperfections
One pair of Zeiss polycarbonate lenses with Duravision Blueprotect coating
Comes with KARRA 578-BLK/GLD frames for Women
Description
Blue light can disrupt sleep
There is a debate within the optical world about blue light which can be a helpful tool against seasonal depression and insomnia. However, blue light can also permanently damage the human eye and the blue light from viewing digital devices at night can disrupt the brain’s production of melatonin, causing sleep disturbances and a dysfunction of the natural circadian rhythm.
Blue-violet light can damage the eye
Blue-violet light has less energy than ultraviolet light and in contrast to UV light (which is mostly absorbed by the front surface of the eye) blue light reaches as far as the retina. Blue-violet light therefore has the potential to cause damage to our eyes. Ultraviolet and blue-violet light can lead to painful inflammation of the front surface of the eye, damage to the lens within the eye itself (e.g., cataracts) and especially damage to the retina (known as macular degeneration). Zeiss DuraVision BlueProtect coating can help to protect they eye from blue-violet light.
Modern digital devices & lighting emit blue light
Most digital devices (smartphones, tablets, computers and modern TV screens) as well as LED and Xenon lights contain a higher proportion of blue light. Blue light regulates the circadian rhythm to ensure alertness in daytime and allow for restful sleep during the night. Viewing these at night can disrupt the brain’s production of melatonin, causing sleep disturbances and a dysfunction of the natural circadian rhythm. Zeiss DuraVision BlueProtect lenses filter the undesirable wavelengths between 440nm and 465nm, while allowing the beneficial blue light through.
ZEISS DuraVision BlueProtect coating
If you mainly wear your glasses indoors, you don't really need a UV block. However, DuraVision Blue Protect blocks blue light radiation irritating or tiring some people's eyes. A blue filter can give sharper vision as different wavelengths are refracted slightly differently by the cornea (front surface of the eye) and the lens within the eye. Not all of wavelengths of light strike at the same focal point on the retina.
SHIPPING & GENARAL INFORMATION
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Please choose Express Mail if you want faster delivery. It's and guarantees second day delivery.
We ship within three business day after payment is cleared. The lenses need to be ordered for your specific Rx.
.99 for Express Mail/.99 for Priority Mail shipping to Canada.
.99 for Express Mail/.99 for Priority Mail shipping to all other countries.
We ship USPS Express Mail (EMS) for international shipping. It takes about 5 business days to deliver.
We love to combine shipping. There's no additional shipping fee for addtional items as long as they are purchased together.